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What Are Stock Market Index/Indices?

How often have you come across a headline that reads something like “90% of people in their twenties believe in getting some form of cardiovascular exercise at least thrice a week,” or “70% of working women do not have a house help at home?” These statistical figures are not absolute – they do not give you the details of every person in the age group or the demographic involved. Instead, they give you a broad idea based on a sample. This technique, called sampling, can help you make inferences and gather insights about many areas in finance, economy, society and more.

The stock market also makes use of this technique to give investors a fair idea of how the markets are moving. Here’s where stock market indices come into the picture. Also known in common parlance as share market indices, they help you gauge the overall behavior of the market.

So, to get into the details, you’ll need to look at various aspects like the stock market index meaning, the types of stock market indices, and why we need them. Let’s begin at the basics and answer the most fundamental question in the context of share market indices – What is a stock market index?

What Are The Types Of Stock Market Indices?

There are different types of stock market indices based on the kind of stocks taken into account to create the index. Here’s a closer look at some of the most common types of indices.

  • Benchmark indices such as BSE Sensex and NSE Nifty
  • Broader indices such as Nifty 50 and BSE 100
  • Indices created based on market capitalization of companies, such as BSE Midcap and BSE Smallcap
  • Sector-specific indices like Nifty FMCG, Nifty Bank Index, CNX IT, and S&P BSE Oil and Gas

For more details read: Types of Stock Market Indices

A Closer Look At The Two Benchmark Indices In The Indian Stock Market

India’s stock markets have two benchmark indices – BSE Sensex and NSE Nifty. Let’s get into the details of these share market indices.

In order to eliminate these limitations and problems associated with physical shares, the National Securities Depository Limited (NSDL) was established in the year 1996. NSDL brought in the concept of Demat accounts, which could be used to electronically store shares and securities of companies. If you own physical shares, you need to convert them to electronic records before being able to use a Demat account. This process of conversion is what is commonly known as dematerialization.

S&P BSE Sensex

Sensex is a blend of the two words – sensitive index. This stock market index was introduced in 1986, making it India’s oldest share market index. The BSE Sensex consists of the top 30 largest and most frequently traded stocks listed in the Bombay Stock Exchange (BSE). Since Standard and Poor’s (S&P), an international credit rating agency, licensed its technical expertise to BSE to construct the index, it is always referred to along with the S&P tag in its name.


Also known as the NSE Nifty, this index was first created in 1996. This share market index consists of the top 50 of the largest and most frequently traded stocks within the NSE. The NIFTY is owned and maintained by India Index Services & Products Limited (IISL), which is a joint-venture organisation between an Indian credit rating agency CRISIL and the National Stock Exchange. In fact, the CNX portion in the CNX NIFTY stands for CRISIL and NSE.

Why Are Stock Market Indices Required?

So, you’ve seen the answer to “what is a stock market index?” And you know the types of indices and what the benchmark indices are. But why do we need these indices?

To begin with, the performance of market indices acts as a nearly accurate indicator of the state of the markets and reflects the general sentiments of investors. These indices also provide investors with a wealth of information that helps them create and implement investment strategies.

Let’s find out more about why stock market indices are required.

They Give You Important Information For Benchmarking

Many traders, investors and other market participants use the performance of the indices as a benchmark for analysing how their investments performed in the stock market. For instance, you can use the performance of NIFTY over a given period to compare it with the actual performance of the stocks in your investment portfolio during that period. This gives you a more accurate representation of the performance of your investments.

They Help Minimize Your Exposure To Risk

One way to outperform the market is by investing in indices through index funds. The risk of underperformance is low in index funds because they contain stocks from several sectors and industries, thereby essentially diversifying your investment portfolio. When you invest in a specific stocks, your corpus might be eroded if those stocks don’t perform well. With stock market indices, however, your exposure to risk is largely reduced.

Read How To Pick Stocks?

They Help Passive Investors

Picking the right stocks to invest in requires a great deal of research. This may be impractical for passive investors, who are looking for avenues to invest in over the long term without constantly monitoring their portfolio actively. If this sounds like you, you could create a portfolio that replicates a stock market index, so you can reduce the costs of research and stock picking without compromising on the quality of your investments.


Stock market indices are extremely useful, and often, in times of market volatility, they act as a cushion for conservative investors. If you’re a beginner to the equity markets, it may be a good idea to start by learning about share market indices and testing the waters here, so you can get a better idea of how the markets work in practice.

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